Automatic clutch



Sept. 12, 1950 D. THO STENSON ,5

AUTOMATIC CLUTCH Filed Dec. 5, 1947 I 2 Sheets-Sheet 2 lNVENTO LEW/5 D. THOSTE. o/v

BY TTTTTTTTTTT 5 HARRIS, K/ECH, FOSTER a HARRIS @YOLVL M Patented Sept. 12, 1950 "the power drive of a motor-driven bicycle, scooter and otherrelatively light-weight vehicles.

It is an object of the invention to provide a gmotor-vehicle having a power transmission in which-an automatic clutch is incorporated and operative to connect and disconnect the motor ata'certain critical speed thereof withoutat- 4 S AT p I AUTOMATIC CLUTCfi Lewis Thostenson; Inglewood, Calif., assignor to Salsbury Corporation, Los Angeles, Calif., a, corporation of California "Application December 5,1947 ,'SerialNo.789,808 t lOlaim. (01.74 .230.24) 1 i r This invention relates generally to motor vein effect, a fixed countershaft or support. "The end of the boss 2| is red ucedin diameter to adapt'it t receive the inner race norn antifriction bearing 24, which may be. of the ball type as herein illustrated or of therolle-r type. The inner race 23 is held in place on the boss 2| by means of a bolt25 as shown in Fig. 2 The tention on the part of the operator of the vehicle. :53

Another object of the invention is to provide, in-a motor vehicle, a power transmission which permits'freeidling of the engine within its normal idling'range, but in which the clutch is automatically engaged to cause movement of the vehicle when the speed of the engine reaches a predetermined value.

Another object of the invention is to provide, in a motor vehicle, power transmission means in which the clutch automatically maintains the engine disconnectedfrom the drive wheel or wheels when the engine is idling so that the vehicle-can be manually propelled in either forward or rearward direction.

A further object is to provide an automatic clutchwhich is simple in construction, economical to manufacture, easy to install and service, and one which is highly efficient in performing its intended function.

-Fufther objects of the invention will be apparent from the following description taken in connection with the accompanying drawings, in

which:

Fight is a perspective view of a motor-operated bicycle, showing the improved automatic clutch installed inthe power transmission of the vehicle; 1 i

Fig. 2 is a cross-sectional view through the automatic clutch, taken on line 22 of Fig. 1, the clutch being shown disengaged;

Fig. 3 a view similar to Fig. 2 but illustrating the clutch'engaged; and

Fig. 4 is a sectional view, taken on line 4-4 of Fig:*2-.

Referring to the drawings in detail, my im- 'i J proved clutch device 5 is shown as applied to use on a -motor-operated bicycle 6. The bicycle 6 may be of any conventional type consisting of frame 1 having a vertical component or post 8, a powerdriven rear wheel 9 and a steerable front wheel ll]. ,An internal combustion engine i2 is mounted omthe frame I and has a drive shaft It to which issecured a small, primary V-belt pulley l5 capableof driving a relatively large V-belt pulley 16, connected .to an operative to rotate the rear wheel '9, :by means to be next described.

-Secured in any suitable manner to the post 8 of the frame I is a u-shaped bracket 20 havin bearing 24 has an outer race 26 which supports an annular clutch-pulley member 2? to-"adapt the member to rotate about the axis -of the boss 2|. The clutch-pulley member 27 has its periphery reduced in diameter at two-points so as to provide a hub portion 28 and a circular boss 29. The member 2'! has an annularperipheral flange 30, one side .or surface 3i of the flange being inclined withvrespect to the vaxis ofthe member. The clutch-pulley memberl'ihas a bore 32 and a counterbore 33 providing a. shoulder 34 therebetween. The outerrace 26 of the bearing 24 isreceived in the counterbore 33 to mount the member}? for rotation on the boss 21, Therace 26 is disposed against the. shoulder 34 and.;is held thereagainst by means of a snap-ring 35 seated in a circular groove 36 formed ingthe counterbore 33. V, v i

Attached to the end of the hub'portion28 of the clutch-pulley member I2'1, byv means i of screws-3,9, is'the hub portion 40 of an intermediate driving member or pulley-4| which has a Vebelt groove 42 in its peripheral portion 43., Extending be,- tween the hub and peripheral portions of the pulley 4| is an annular web 44 providedwitha. conical, concave surface 4 5; ;,A V-belt Misconnected between and surrounds the pulleys., l5 and M so that when the engine I2 is operating and its drive shaft l4 is rotating, 'the pulley" 4] and the clutch-pulley member..2'i connected therganith are rotated in unison qn the ball bearmg r,

Slidable axially on tl'iehub portion l28 of'the clutch-pulley member 2'! is the hub 49 of .a-sec=- ond annular clutch-pulley member 50, the two members being connected for unitary rotation by means'of a key 5] interposedtherebetween, The member 50 has an inclined circumferential flange 52 was to provide .at one side a convex, conical face 53 which cooperates with the face 3| ofthe member 21 to provide an annular V:belt; -groove 54 therebetween. Due to the fact that themember 50, can slide axially, relative to the member 21, the conical face 53 can be moved towardjand away from the correspondingv face 3| of the mom:- ber 21 so that a V-belt 55 disposed in the groove 54 and extending between the clutch-pulley 5,0, 2l and the pulley I6 can be tightened and loosened to connect and disconnect thedrivebetween the engine 12 and the rear -wheel9. The inclined flange 52 also provides a concave, conical face 56 which is used for the purpose to be ex.-

a horizontally projecting boss 2| which Provides, 60 plained hereinafter.

and 50 with its periphery located inwardly of; their respective flanges 30 and 52 so that when the member 50 is shifted toward the left, as

viewed in Fig. 2, and the belt 5.5 is permitted to move inwardly toward the axi'sof rotation of the clutch-pulley 21, 5D, the belt 55 will seat againstthe ring 58 which is freely rotatable on the rollers 51. The belt 55 is thus prevented from engaging the boss 29 of the member 21 so that it cannot be driven from the member when the engine [2 is operated at low speed.

The clutch-pulley member '59 is adapted to be shifted toward the right inresponse to an in- ;orease in speed of the engine in excess of an idling speed ,by centrifugally-operated means. This last-named means consists of a series of balls 60 which are .disposed in the space between the flange portion 52 .of the .member 56 and the 'web' M' of the intermediate pulley 4! and which :may be carried by a spring element Bl so that the point of release of the clutch .is determined by the -contr.a.ctive strength of the element. When the engine is stopped or is idling, the balls 60 are adapted .to revolve around the hub '49 of the member 50, which .is then in the position .shown inliig. 2, to permit thedriving belt 55 to engage .the rotatable ring 58. However, when the engine 12 is accelerated to a speed in excess .ofz'the idlingspeed, the balls .68 move radially out- Wardrunder the influence of centrifugal force and :thus engage the conical surfaces 55 and d5 of the respective parts 50 and M.

The efiect of this centrifugal wedging action :is it!) shift the clutch-pulley member 50 toward the right so that the V-shaped groove 54 is narrowed .and the .belt 55 thus clutched to the rotating members 58 and Z-Tto be driven thereby. In this manner the-driven pulleylfi and the rear wheel 9 are rotated to-propel the vehicle along the ground, the speed of rotation of the wheel being proportional to the speed of the engine. Disregarding slippage; which can occur at the start of movementof the vehicle, when inertia is greatest and must be overcome, the speed ratio is governed by the relative diameters of the pulleys l5, 4!, 2150 a-nd l6.

When it is desired to arrest the forward progress of the vehicle "6, the operator merely closes the engine throttle to retard the speed of the engine and during this time the rotative speed i of the wheel '9 is reduced, the balls 60 remaining =in-'the position shown in Fig. 3. As the speed of the engine 12 is reduced to an idling speed, however, the balls 60 are no longer subjected to centrifugal force of" great magnitude and thus *the balls move radially inward to permit the clutch-pulley member '50 to movetoward the left *(Fig. "2) and to thus slacken the be1t55 to declu-tch the driveso that propulsion of the vehicle is discontinued. It is thus seen that the drive is clutched and declutched automatically in response to the speed of the engine and -'without any client or attention on the part of "the operator of the wehicle. I

When therengine 1 2 "is inoperative or when it is -idling,:the vehicle can be maneuvered manually along the ground, either in a forward or rear ward direction, it being noted that at :this time the driving belt 55 is slack and merely rotates the ring-58 without rotating :the. clutch-pulley 21, 1:59.]Itwill be apparent that the present improved automatic clutch is adaptable for use in various power transmission mechanisms, especially those employed in light-weight motor vehicles of the type herein illustrated or others now muse.

While .I have herein shown and described the automatic clutch as embodied in a preferred form of construction, by way of example, it will be apparent thatvarious changes might be made in the structure without departing from the spirit of the invention. Consequently, I do not wish to be limited in this respect but desire to be .af- :forded the full scope of the appended claim.

I claim as ,my invention: An automatic clutch device, comprising: a fixed support; an antifriction bearing carried by said support; retaining means for mtaining said hearing on said support; a clutch pulley including a first clutch member rotatableon said bearing and having a hub, a second .clutch member having .a hub surrounding said hub of said first member, and hey means between said first and second members for connecting said members forunitary rotation While permitting .relati-ve axial sliding movement therebetween, said members having adjacent conical faces defining a V-shaped peripheral groove therebetween, said second member having a concave tapered surface in its side opposite its conical face; a V-bel-t extending around said clutch pulley in said .groove thereof andedapted to transmit power to .a dr-ivenpulleyg a rotary driving member connected to said hub of said first-clutch member and adapted to be rotated .:at .difierent speeds, said driving member having :aeoncave taperedsurface in v its-side adjacent said second clutch vmember, said-tapered surfaces of said driving member and said second member defining therebetween an annular space .of decreasing width ,in a direction radially out- .ward from the axis of rotation of .said .driizing member and said clutch pulley, said-driving memher having *a peripheral portion overhanging said annular space and formed with .a .V--,-groove;;a -V-belt disposed in said last-named 1V :erooveand adapted to be driven from a prime moverg and .centriiusally operated rballs disposed in said an- 6011111181! Space and engageable with said tapered surfaces of said adriving member, andv said second clutch member, said balls being operative, infresponse to increase and decrease in the 'rotative speed of said driving member above and below 55 a predetermined value, to slide saidsecondmemher toward and away from saidfirst-memberso as to narrow and widen said ,groove to tighten and 31005611 said belt.

LEWIS D. THOSTENS ON.

REFERENCES GITED .The following references. are of record-tin the his of this patent: Y 

